The users of workstations use a PC as a computer dedicated to their personal work. This work is controlled by the user in dialogs he conducts in the foreground. By entering control information, the user decides what the computer should do next, in most cases working on data the user has entered on the screen. However, modern PCs running under a modern operating system like IBM OS/2 WARP can execute several strings of instructions or tasks in parallel, by switching the processing unit between tasks whenever some input/output operation, e.g. waiting for user input, can not fully utilize the power of the processor. And yet in many cases, when a user issues a request for an activity to the system, he may have to wait until the system can start the requested dialog or interaction because the requested activity requires preparatory work by the system.